Synthesis of methyl ethyl sulfide and related production systems

ABSTRACT

The present invention discloses processes for producing methyl ethyl sulfide by contacting dimethyl sulfide and diethyl sulfide in the presence of a suitable catalyst. Methyl ethyl sulfide can be used as an odorant in natural gas. Integrated mercaptan and sulfide manufacturing systems and integrated methods for making mercaptans and sulfides also are disclosed.

REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of co-pending U.S. PatentApplication 16/291,014, filed on Mar. 4, 2019, now U.S. Pat. No.10,538,488, which claims the benefit of U.S. Provisional PatentApplication No. 62/638,344, filed on Mar. 5, 2018, and U.S. ProvisionalApplication No. 62/753,965, filed on Nov. 1, 2018, the disclosures ofwhich are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present disclosure relates to integrated mercaptan and sulfidemanufacturing systems and integrated methods for making mercaptans andsulfides, and more particularly, relates to such systems and methods inwhich methyl ethyl sulfide is produced by reacting dimethyl sulfide anddiethyl sulfide in the presence of a catalyst.

BACKGROUND OF THE INVENTION

Methyl ethyl sulfide can be prepared by reacting a suitable symmetricalsulfide with a suitable mercaptan, but this technique results insignificant mercaptan byproducts. Methyl ethyl sulfide also can beprepared by reacting sodium methyl mercaptide and ethyl chloride, butsignificant waste products also are produced. Thus, the presentinvention is generally directed to a synthesis scheme to produce methylethyl sulfide in high yield and with minimal reaction byproducts.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify required oressential features of the claimed subject matter. Nor is this summaryintended to be used to limit the scope of the claimed subject matter.

Integrated mercaptan and sulfide manufacturing systems are describedherein. Such systems can comprise (i) a mercaptan production systemcapable of producing methyl mercaptan and dimethyl sulfide from methanoland H₂S and capable of producing ethyl mercaptan and diethyl sulfidefrom ethanol and H₂S; (ii) a DMDS production system for consuming atleast a portion of the methyl mercaptan from the mercaptan productionsystem, wherein the DMDS production system is capable of producingdimethyl disulfide from the methyl mercaptan; (iii) an ETE productionsystem for consuming at least a portion of the ethyl mercaptan from themercaptan production system, wherein the ETE production system iscapable of producing ethylthioethanol from the ethyl mercaptan; and (iv)a MES production system for consuming at least a portion of the dimethylsulfide and the diethyl sulfide from the mercaptan production system,wherein the MES production system is capable of producing methyl ethylsulfide from the dimethyl sulfide and the diethyl sulfide.

Integrated methods for producing mercaptans and sulfides also areprovided herein. Such methods can comprise (a) reacting methanol and H₂Sto form methyl mercaptan and dimethyl sulfide, (b) reacting ethanol andH₂S to form ethyl mercaptan and diethyl sulfide, (c) reacting at least aportion of the methyl mercaptan with hydrogen peroxide and sodiumhydroxide to form dimethyl disulfide, (d) reacting at least a portion ofthe ethyl mercaptan with ethylene oxide to form ethylthioethanol, and(e) reacting at least a portion of the dimethyl sulfide and the diethylsulfide to form methyl ethyl sulfide.

Consistent with aspects of this invention, a process for producingmethyl ethyl sulfide also is disclosed herein, and this process cancomprise contacting dimethyl sulfide, diethyl sulfide, and a catalyst toform a reaction mixture containing the methyl ethyl sulfide.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects may bedirected to various feature combinations and sub-combinations describedin the detailed description.

BRIEF DESCRIPTION OF THE FIGURES

The following figures form part of the present specification and areincluded to further demonstrate certain aspects of the presentinvention. The invention may be better understood by reference to one ormore of these figures in combination with the detailed description andexamples.

FIG. 1 illustrates an integrated mercaptan and sulfide manufacturingsystem consistent with an aspect of the present invention.

FIG. 2 presents a gas chromatograph plot of the blended feed of dimethylsulfide and diethyl sulfide, which was used in Examples 1-15.

FIG. 3 presents a gas chromatograph plot of the reaction mixture ofExample 3 containing methyl ethyl sulfide.

FIG. 4 presents a gas chromatograph plot of a reaction mixturecontaining methyl ethyl sulfide, produced using a CoMo catalyst.

FIG. 5 presents a gas chromatograph plot of a reaction mixturecontaining methyl ethyl sulfide, produced using a γ-alumina catalyst.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2^(nd) Ed (1997), can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

Herein, features of the subject matter are described such that, withinparticular aspects, a combination of different features can beenvisioned. For each and every aspect and each and every featuredisclosed herein, all combinations that do not detrimentally affect thesystems, compositions, processes, or methods described herein arecontemplated with or without explicit description of the particularcombination. Additionally, unless explicitly recited otherwise, anyaspect or feature disclosed herein can be combined to describe inventivesystems, compositions, processes, or methods consistent with the presentdisclosure.

Generally, groups of elements are indicated using the numbering schemeindicated in the version of the periodic table of elements published inChemical and Engineering News, 63(5), 27, 1985. In some instances, agroup of elements can be indicated using a common name assigned to thegroup; for example, alkali metals for Group 1 elements, alkaline earthmetals for Group 2 elements, transition metals for Group 3-12 elements,and halogens or halides for Group 17 elements.

The term “hydrocarbon” whenever used in this specification and claimsrefers to a compound containing only carbon and hydrogen, whethersaturated or unsaturated. Other identifiers can be utilized to indicatethe presence of particular groups in the hydrocarbon (e.g., halogenatedhydrocarbon indicates the presence of one or more halogen atomsreplacing an equivalent number of hydrogen atoms in the hydrocarbon).The term “hydrocarbyl group” is used herein in accordance with thedefinition specified by IUPAC: a univalent group formed by removing ahydrogen atom from a hydrocarbon (that is, a group containing onlycarbon and hydrogen). Non-limiting examples of hydrocarbyl groupsinclude alkyl, alkenyl, aryl, and aralkyl groups, amongst other groups.

For any particular compound or group disclosed herein, any name orstructure (general or specific) presented is intended to encompass allconformational isomers, regioisomers, stereoisomers, and mixturesthereof that can arise from a particular set of substituents, unlessotherwise specified. The name or structure (general or specific) alsoencompasses all enantiomers, diastereomers, and other optical isomers(if there are any) whether in enantiomeric or racemic forms, as well asmixtures of stereoisomers, as would be recognized by a skilled artisan,unless otherwise specified. For instance, a general reference to pentaneincludes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane; and ageneral reference to a butyl group includes a n-butyl group, a sec-butylgroup, an iso-butyl group, and a t-butyl group.

Unless otherwise specified, the term “substituted” when used to describea group, for example, when referring to a substituted analog of aparticular group, is intended to describe any non-hydrogen moiety thatformally replaces a hydrogen in that group, and is intended to benon-limiting. Also, unless otherwise specified, a group or groups canalso be referred to herein as “unsubstituted” or by equivalent termssuch as “non-substituted,” which refers to the original group in which anon-hydrogen moiety does not replace a hydrogen within that group.Moreover, unless otherwise specified, “substituted” is intended to benon-limiting and include inorganic substituents or organic substituentsas understood by one of ordinary skill in the art.

The terms “contact product,” “contacting,” and the like, are used hereinto describe methods and compositions wherein the components arecontacted together in any order, in any manner, and for any length oftime, unless otherwise specified. For example, the components can becontacted by blending or mixing. Further, unless otherwise specified,the contacting of any component can occur in the presence or absence ofany other component of the methods and compositions described herein.Combining additional materials or components can be done by any suitablemethod. Further, the term “contact product” includes mixtures, blends,solutions, slurries, reaction products, and the like, or combinationsthereof. Although “contact product” can, and often does, includereaction products, it is not required for the respective components toreact with one another. Consequently, depending upon the circumstances,a “contact product” can be a mixture, a reaction mixture, or a reactionproduct. Likewise, “contacting” two or more components can result in areaction product or a reaction mixture.

In this disclosure, while systems, compositions, and processes aredescribed in terms of “comprising” various components or steps, thesystems, compositions, and processes also can “consist essentially of”or “consist of” the various components or steps, unless statedotherwise.

The terms “a,” “an,” and “the” are intended to include pluralalternatives, e.g., at least one. For instance, the disclosure of “acatalyst” is meant to encompass one catalyst, or mixtures orcombinations of more than one catalyst, unless otherwise specified.

Several types of ranges are disclosed in the present invention. When arange of any type is disclosed or claimed, the intent is to disclose orclaim individually each possible number that such a range couldreasonably encompass, including end points of the range as well as anysub-ranges and combinations of sub-ranges encompassed therein. Forexample, the molar ratio of dimethyl sulfide to diethyl sulfide can bein certain ranges in various aspects of this invention. By a disclosurethat the molar ratio of dimethyl sulfide to diethyl sulfide can be in arange from about 1.5:1 to about 10:1, the intent is to recite that themolar ratio can be any ratio in the range and, for example, can be equalto about 1.5:1, about 2:1, about 3:1, about 4:1, about 5:1, about 6:1,about 7:1, about 8:1, about 9:1, or about 10:1. Additionally, the molarratio can be within any range from about 1.5:1 to about 10:1 (forexample, from about 2:1 to about 6:1), and this also includes anycombination of ranges between about 1.5:1 and about 10:1 (for example,the ratio can be in a range from about 1.5:1 to about 5:1, or from about7:1 to about 9:1). Further, in all instances, where “about” a particularvalue is disclosed, then that value itself is disclosed. Thus, thedisclosure of a molar ratio from about 1.5:1 to about 10:1 alsodiscloses a molar ratio from 1.5:1 to 10:1 (for example, from 2:1 to6:1), and this also includes any combination of ranges between 1.5:1 and10:1 (for example, the ratio can be in a range from 1.5:1 to 5:1, orfrom 7:1 to 9:1). Likewise, all other ranges disclosed herein should beinterpreted in a manner similar to this example.

The term “about” means that amounts, sizes, formulations, parameters,and other quantities and characteristics are not and need not be exact,but may be approximate including being larger or smaller, as desired,reflecting tolerances, conversion factors, rounding off, measurementerrors, and the like, and other factors known to those of skill in theart. In general, an amount, size, formulation, parameter or otherquantity or characteristic is “about” or “approximate” whether or notexpressly stated to be such. The term “about” also encompasses amountsthat differ due to different equilibrium conditions for a compositionresulting from a particular initial mixture. Whether or not modified bythe term “about,” the claims include equivalents to the quantities. Theterm “about” can mean within 10% of the reported numerical value, andoften within 5% of the reported numerical value.

All disclosed product yields are based on the limiting reactant in therespective reaction, unless explicitly stated otherwise. For example,the limiting reactant in a process for synthesizing methyl ethyl sulfidecan be diethyl sulfide, therefore, the conversions and yields are basedon the initial quantity of the diethyl sulfide.

Although any methods, devices, and materials similar or equivalent tothose described herein can be used in the practice or testing of theinvention, the typical methods, devices, and materials are hereindescribed.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein are processes for producing methyl ethyl sulfide bycontacting dimethyl sulfide and diethyl sulfide with a catalyst in fixedbed reactor. These processes can be conducted with an excess of dimethylsulfide, such that diethyl sulfide is the limiting reactant.Advantageously, the disclosed processes have excellent conversion of thediethyl sulfide and yield to methyl ethyl sulfide.

The methyl ethyl sulfide produced in accordance with this disclosure canbe used as an odorant in natural gas. Beneficially, methyl ethyl sulfidehas a boiling point in a desirable temperature range and a low freezingpoint, and is less prone to odor fade as compared to mercaptan-basedodorants.

Also disclosed are integrated mercaptan and sulfide manufacturingsystems and integrated methods for making mercaptans and sulfides, andthese systems and methods incorporate the production of methyl ethylsulfide from dimethyl sulfide and diethyl sulfide.

Synthesizing methyl ethyl sulfide

Aspects of this invention are directed to a process for producing methylethyl sulfide. This process can comprise contacting (a) dimethylsulfide, (b) diethyl sulfide, and (c) a catalyst, to form a reactionmixture comprising the methyl ethyl sulfide. Generally, the features ofthis process for producing methyl ethyl sulfide (e.g., the catalyst andthe conditions under which the methyl ethyl sulfide is formed, amongothers) are independently described herein and these features can becombined in any combination to further describe the disclosed process toproduce methyl ethyl sulfide. Moreover, additional process steps can beperformed before, during, and/or after the contacting/reacting step ofthis process, and can be utilized without limitation and in anycombination to further describe the methyl ethyl sulfide synthesisprocess, unless stated otherwise.

Generally, the appropriate procedure for the contacting (or reacting)step in the process for producing methyl ethyl sulfide is notparticularly limited. For instance, the step of contacting (or reacting)dimethyl sulfide, diethyl sulfide, and the catalyst can comprisecontacting the dimethyl sulfide, diethyl sulfide, and catalyst in anyorder that produces an acceptable yield of methyl ethyl sulfide.Typically, the dimethyl sulfide and the diethyl sulfide are combinedfirst, followed by contacting the mixture of dimethyl sulfide anddiethyl sulfide with the catalyst.

The processes to produce methyl ethyl sulfide can be conducted at anysuitable temperature and for any suitable period of time. Representativeand non-limiting ranges for the temperature of the contacting step (orfor the formation of the methyl ethyl sulfide) can include from about200° C. to about 500° C., from about 250° C. to about 500° C., fromabout 200° C. to about 450° C., from about 250° C. to about 450° C.,from about 125° C. to about 400° C., from about 200° C. to about 400°C., from about 200° C. to about 350° C., from about 250° C. to about400° C., or from about 250° C. to about 350° C. These temperature rangesalso are meant to encompass circumstances where the contacting step (orthe formation of the methyl ethyl sulfide) is performed at a series ofdifferent temperatures, instead of at a single fixed temperature,falling within the respective temperature ranges, wherein at least onetemperature is within the recited ranges.

Similarly, the time period for contacting the dimethyl sulfide, thediethyl sulfide, and the catalyst (or for the formation of the methylethyl sulfide) is not particularly limited, and can be conducted for anysuitable period of time. In some aspects, the time period can be leastabout 1 minute, at least about 5 minutes, at least about 10 minutes, atleast about 30 minutes, at least about 1 hour, at least about 2 hours,at least about 5 hours, or at least about 10 hours. In other aspects,the time period can be from about 30 seconds to about 48 hours, fromabout 1 minute to about 24 hours, from about 5 minutes to about 8 hours,from about 30 minutes to about 8 hours, or from about 1 hour to about 6hours.

Often, the process for forming the methyl ethyl sulfide can be a flowprocess and/or a continuous process. In such circumstances, the limitingreactant-catalyst contact time (or reaction time) can be expressed interms of weight hourly space velocity (WHSV)—the ratio of the weight ofthe limiting reactant which comes in contact with a given weight ofcatalyst per unit time (units of g/g/hr).

While not limited thereto, the WHSV employed for the process ofproducing methyl ethyl sulfide can have a minimum value of 0.01, 0.02,0.05, 0.1, 0.25, or 0.5; or alternatively, a maximum value of 5, 4, 3,2.5, 2, or 1. Generally, the WHSV can be in a range from any minimumWHSV disclosed herein to any maximum WHSV disclosed herein. In anon-limiting aspect, the WHSV can be in a range from about 0.01 to about5; alternatively, from about 0.01 to about 3; alternatively, from about0.01 to about 1; alternatively, from about 0.02 to about 4;alternatively, from about 0.02 to about 3; alternatively, from about0.05 to about 2; alternatively, from about 0.05 to about 1;alternatively, from about 0.1 to 4; alternatively, from about 0.25 toabout 3; alternatively, from about 0.25 to about 2; alternatively, fromabout 0.5 to about 4; alternatively, from about 0.5 to about 2; oralternatively, from about 0.5 to about 1. Other WHSV ranges are readilyapparent from this disclosure. Any suitable reactor or vessel can beused to form the methyl ethyl sulfide, non-limiting examples of whichcan include a flow reactor, a continuous reactor, a packed tube, and astirred tank reactor, including more than one reactor in series or inparallel, and including any combination of reactor types andarrangements.

In one aspect, the process for producing methyl ethyl sulfide cancomprise contacting the dimethyl sulfide and the diethyl sulfide in thevapor phase with the catalyst (e.g., the solid catalyst). Additionallyor alternatively, the process for producing methyl ethyl sulfide cancomprise contacting the dimethyl sulfide and the diethyl sulfide with afixed bed of the catalyst.

While not being limited thereto, the contacting step and/or theformation of the methyl ethyl sulfide can be conducted at a reactionpressure in a range from about 50 to about 850 psig (344 to 5860 kPag).Other representative and non-limiting ranges for the reaction pressurecan include from about 50 to about 500 psig (344 to 3447 kPag), fromabout 100 to about 400 psig (689 to 2758 kPag), from about 150 to about400 psig (1034 to 2758 kPag), from about 200 to about 450 psig (1379 to3103 kPag), or from about 200 to about 350 psig (1379 to 2413 kPag).

The molar ratio of dimethyl sulfide to diethyl sulfide (DMS:DES) is notparticularly limited, and generally can fall within a range from about10:1 to about 1:10. Typical ranges for the molar ratio of the dimethylsulfide to diethyl sulfide (DMS:DES) can include, but are not limitedto, from about 5:1 to about 1:5, from about 4:1 to about 1:4, from about3:1 to about 1:3, from about 2:1 to about 1:2, or from about 1.5:1 toabout 1:1.5.

Certain ratios of components during the contacting step can proveadvantageous with respect to the yield and purity of the resultantmethyl ethyl sulfide. In one aspect, the molar ratio of DMS:DES can begreater than about 1:1, greater than about 1.2:1, greater than about1.5:1, greater than about 2:1, greater than about 3:1, or greater thanabout 5:1. In such circumstances, the diethyl sulfide can be thelimiting reactant in the process for producing the methyl ethyl sulfide.Typical non-limiting ranges for the molar ratio of DMS:DES, therefore,can include from about 1.2:1 to about 15:1, from about 1.5:1 to about10:1, from about 1.5:1 to about 6:1, from about 2:1 to about 10:1, fromabout 4:1 to about 20:1, or from about 2:1 to about 6:1. It should benoted that an excess of the dimethyl sulfide can promote greater yieldof the methyl ethyl sulfide compound.

Optionally, the process for producing methyl ethyl sulfide can furtherinclude an additional sulfur-containing reactant. That is, the processcan comprise contacting the dimethyl sulfide, the diethyl sulfide, thecatalyst, and a sulfur-containing compound. Illustrative andnon-limiting examples of the sulfur-containing compound include H₂S,CS₂, di-tert-butyl polysulfide, and the like, as well as any combinationthereof. While not wishing to be bound by the following theory, it isbelieved that small amounts of such sulfur-containing materials canimprove the yield of the methyl ethyl sulfide. Any suitable amount ofthe sulfur-containing compound can be used, from an amount greater thanzero and typically less than or equal to about 5 mol %. More often, theaddition amount can be less than or equal to about 3 mol %, or less thanor equal to about 1 mol %. These mole percentages are based on the molesof the limiting reactant (e.g., diethyl sulfide). The di-tert-butylpolysulfide material is low in odor and non-volatile, and therefore canbe conveniently used in the disclosed processes.

The processes described herein result in an unexpectedly high conversionof the limiting reactant and/or yield to the methyl ethyl sulfide. Inone aspect, the minimum conversion (or yield) can be at least about 50%,at least about 60%, at least about 70%, at least about 80%, at leastabout 90%, or at least about 95%. Additionally, the maximum conversion(or yield) can be about 97%, about 98%, about 99%, or about 99.5%, andcan approach 100% conversion of the limiting reactant (or yield of themethyl ethyl sulfide). Generally, the conversion (or yield) can be in arange from any minimum conversion (or yield) disclosed herein to anymaximum conversion (or yield) disclosed herein. Non-limiting ranges ofconversion (or yield) can include from about 50% to about 99.5%, fromabout 80% to about 99%, from about 90% to about 98%, or from about 95%to 100%. For conversion, the percentages are the amount of the limitingreactant converted based on the initial amount of the limiting reactant.The yield values are mole percentages and are based on the moles ofmethyl ethyl sulfide produced to moles of the limiting reactant. In someaspects, these conversions (or yields) can be achieved in a batchprocess, while in other aspects, these conversions (or yields) can beachieved in a flow or continuous process, such as, for example, a singlepass or multiple passes through a reactor (e.g., a fixed bed reactor).

Also unexpectedly, continuous flow processes for producing the methylethyl sulfide in accordance with this invention have unexpectedly highsingle pass conversions of the limiting reactant (or single pass yieldsto the methyl ethyl sulfide). In one aspect, the minimum single passconversion (or yield) can be at least about 40%, at least about 50%, atleast about 60%, at least about 70%, at least about 80%, or at leastabout 85%. Additionally, the maximum single pass conversion (or yield)can be about 90%, about 95%, about 98%, or about 99%, and can approach100% conversion of the limiting reactant (or yield of the methyl ethylsulfide), depending upon the reaction conditions. Generally, the singlepass conversion (or yield) can be in a range from any minimum singlepass conversion (or yield) disclosed herein to any maximum single passconversion (or yield) disclosed herein. Non-limiting ranges of singlepass conversion (or yield) can include from about 40% to about 90%, fromabout 50% to about 90%, from about 60% to about 95%, from about 70% toabout 98%, or from about 80% to 100%.

The processes to produce methyl ethyl sulfide disclosed herein typicallyresult in a crude reaction mixture containing the methyl ethyl sulfide,residual reactants, and relatively minor amounts of byproducts (e.g.,mercaptans, sulfide heavies). Beneficially, and unexpectedly, the amountof mercaptan products (such as methyl mercaptan and/or ethyl mercaptan)in the reaction mixture is very low. For instance, in one aspect, thereaction mixture can contain less than or equal to about 5 wt. %mercaptan products (or less than or equal to about 5 wt. % methylmercaptan, or less than or equal to about 5 wt. % ethyl mercaptan),while in another aspect, the reaction mixture can contain less than orequal to about 3 wt. % mercaptan products (or less than or equal toabout 3 wt. % methyl mercaptan, or less than or equal to about 3 wt. %ethyl mercaptan), and in yet another aspect, the reaction mixture cancontain less than or equal to about 2 wt. % (or 1 wt. %) mercaptanproducts (or less than or equal to about 2 wt. % (or 1 wt. %) methylmercaptan, or less than or equal to about 2 wt. % (or 1 wt. %) ethylmercaptan).

In many instances, it can be desirable to isolate the methyl ethylsulfide from the reaction mixture for sale or for use in furtherindustrial processes. Accordingly, in certain aspects, the process forproducing methyl ethyl sulfide can further comprise a step of isolatingthe methyl ethyl sulfide from the reaction mixture to form a productstream containing the methyl ethyl sulfide. Isolation of the methylethyl sulfide can employ any suitable technique for separating themethyl ethyl sulfide from other components of the reaction mixture, inorder to form a product stream containing the methyl ethyl sulfide. Suchtechniques can include, but are not limited to, extraction, filtration,evaporation, or distillation, as well as combinations of two or more ofthese techniques. In particular aspects of this invention, the isolatingstep utilizes distillation at any suitable pressure (one or more thanone distillation column can be used). Advantageously, the low levels ofmercaptans in the reaction mixture make isolating the methyl ethylsulfide via distillation a relatively straightforward process.

Additionally, other components of the reaction mixture (e.g., dimethylsulfide and diethyl sulfide) can be recovered and recycled to thereactor. In such instances, the limiting reactant can be recycled toextinction, such that all or substantially all (>99 mol %) of thelimiting reactant (e.g., diethyl sulfide) is converted to the methylethyl sulfide (or to a byproduct).

After isolating, and unexpectedly, the processes to produce methyl ethylsulfide disclosed herein can result in a high yield of the methyl ethylsulfide in the product stream. Generally, the methyl ethyl sulfide canbe produced in a yield of at least about 40 mol %, and more often, atleast about 60 mol %, at least about 70 mol %, at least about 80 mol %,at least about 90 mol %, or at least about 95 mol %, and often as highas 98-100 mol %, in the product stream. This yield is based on the molesof the limiting reactant, which is often the diethyl sulfide. Generally,purification steps to isolate a desired product from a crude reactionmixture reduce the overall yield of the desired product. However,consistent with this invention, the isolated methyl ethyl sulfide can berecovered in a yield similar to that of the crude methyl ethyl sulfide.

After the isolating step, the methyl ethyl sulfide can have a purity ofat least about 80 wt. %, at least about 85 wt. %, at least about 90 wt.%, at least about 95 wt. %, at least about 97 wt. %, or at least about99 wt. %, in the product stream. The purity is based on the weight ofthe methyl ethyl sulfide in the product stream to the total weight ofthe product stream.

The catalyst compositions used in the processes disclosed herein are notparticularly limited, so long as they are able to promote a reactionbetween dimethyl sulfide and diethyl sulfide to produce methyl ethylsulfide, as described herein. In one aspect, the catalyst can compriseany suitable solid hydrotreating catalyst. In another aspect, thecatalyst can comprise a CoMo catalyst, a NiMo catalyst, and the like, aswell as any combination thereof. In yet another aspect, the catalyst(e.g., the CoMo and/or NiMo catalyst) can be pre-sulfided to increasethe conversion of the limiting reactant and the yield of the methylethyl sulfide.

As would be recognized by one of skill in the art, the catalyst can besupported on any suitable solid oxide or like material. Thus, thecatalyst can further comprise a support or solid oxide, illustrativeexamples of which can include silica, alumina, silica-alumina, aluminumphosphate, zinc aluminate, zirconia, thoria, and the like. Combinationsof more than one support material can be used for the catalyst.

Consistent with another aspect of this invention, the catalyst does notcontain a transition metal. For instance, the catalyst can comprise (orconsist essentially of, or consist of) γ-alumina in one aspect of thisinvention. In another aspect, the catalyst can comprise a molecularsieve or a zeolite (a crystalline aluminosilicate), such as a Y-zeolite(zeolite Y) or a X-zeolite (zeolite X). Zeolites can exhibit a networkof SiO₄ and AlO₄ tetrahedra in which aluminum and silicon atoms arecrosslinked in a three-dimensional framework by sharing oxygen atoms. Inthe framework, the ratio of oxygen atoms to the total of aluminum andsilicon atoms can be equal to 2. The framework exhibits a negativeelectrovalence that typically can be balanced by the inclusion ofcations within the crystal, such as metals, alkali metals, alkalineearth metals, hydrogen, or combinations thereof.

The Y-zeolite (zeolite Y) and X-zeolite (zeolite X) can have an averagepore diameter in a range of from about 7 Å to about 12 Å. The Si:Alratio for a X-zeolite is less than that for a Y-zeolite. Often, thezeolite can be bound with a support matrix (or binder), non-limitingexamples of which can include silica, alumina, magnesia, boria, titania,zirconia, various clays, and the like, including mixed oxides thereof,as well as mixtures thereof.

In some aspects, the catalyst can comprise supported CoMo and an alkalior alkaline earth metal hydroxide, such as described in U.S. Pat. No.4,277,623, incorporated herein by reference in its entirety. Forinstance, the catalyst can contain 3-4 wt. % cobalt oxide and 15-16 wt.% molybdenum oxide supported on alumina, although the respective amountsof Co and Mo are not limited thereto. Illustrative examples of suitablehydroxides can include, but are not limited to, lithium hydroxide,sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesiumhydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, andthe like, as well as combinations thereof. The hydroxide component canbe in any form, but beneficially for the processes disclosed herein, canbe in pellet form for use in a fixed or packed bed reactorconfiguration. The relative amounts of the supported CoMo component andthe hydroxide component are not particularly limited, although an excessof the hydroxide component, on a weight basis, often can be used.

In some aspects, the catalyst can comprise a metal salt compound,typically palladium (II), rhodium (III), platinum (II), and/or copper(I) or (II) salt compounds, as described in U.S. Pat. No. 4,005,129,incorporated herein by reference in its entirety. The catalyst also caninclude an aliphatic, cycloaliphatic, aromatic, or heterocyclic amine orammonia, as well as copper (II) or iron (III) oxidant compounds—e.g., acopper (II) oxalate, sulfate, acetate, or trifluoroacetate oxidant saltcompound. Representative metal salt compounds can include, but are notlimited to, palladium (II) chloride, copper (II) chloride, rhodium (III)chloride, copper (II) iodide, palladium (II) sulfate, palladium (II)oxalate, palladium (II) acetate, palladium (II) iodide, rhodium (III)bromide, platinum (II) chloride, platinum (II) sulfate, and the like, aswell as combinations thereof. Any or all of the catalyst components canbe supported on any suitable support material or solid oxide.

Integrated Mercaptan and Sulfide Manufacturing Systems

An integrated mercaptan and sulfide manufacturing system consistent withaspects of the present invention can comprise (i) a mercaptan productionsystem capable of producing (or configured to produce) methyl mercaptanand dimethyl sulfide from methanol and H₂S, and capable of producing (orconfigured to produce) ethyl mercaptan and diethyl sulfide from ethanoland H₂S, (ii) a DMDS production system for consuming at least a portionof the methyl mercaptan from the mercaptan production system, whereinthe DMDS production system is capable of producing (or configured toproduce) dimethyl disulfide from the methyl mercaptan, (iii) an ETEproduction system for consuming at least a portion of the ethylmercaptan from the mercaptan production system, wherein the ETEproduction system is capable of producing (or configured to produce)ethylthioethanol from the ethyl mercaptan, and (iv) a MES productionsystem for consuming at least a portion of the dimethyl sulfide and thediethyl sulfide from the mercaptan production system, wherein the MESproduction system is capable of producing (or configured to produce)methyl ethyl sulfide from the dimethyl sulfide and the diethyl sulfide.

The mercaptan production system is capable of producing (or configuredto produce) methyl mercaptan and dimethyl sulfide from methanol and H₂Sand is further capable of producing (or configured to produce) ethylmercaptan and diethyl sulfide from ethanol and H₂S. The relative amountof methyl mercaptan (or ethyl mercaptan) produced as compared to theamount of dimethyl sulfide (or diethyl sulfide) can vary depending uponthe process conditions and the amount of excess H₂S used in therespective reaction. While not being limited thereto, at least about 70wt. %, 80 wt. %, 85 wt. %, or 90 wt. % of the reaction products aremethyl mercaptan (or ethyl mercaptan), with the amount of dimethylsulfide (or diethyl sulfide) typically less than 30 wt. %, 20 wt. %, 15wt. %, or 10 wt. % of the reaction products.

In the mercaptan production system, isolated product streams of methylmercaptan (or ethyl mercaptan) and dimethyl sulfide (or diethyl sulfide)can be produced using any suitable separations technique (e.g.,distillation) or a combination of suitable techniques.

The DMDS production system can consume at least a portion of the methylmercaptan from the mercaptan production system. While not being limitedthereto, at least about 75 wt. % of the methyl mercaptan from themercaptan production system generally is consumed in the DMDS productionsystem. In some aspects, at least about 85 wt. %, at least about 95 wt.%, at least about 99 wt. %, or all or substantially all, of the methylmercaptan from the mercaptan production system can be consumed in theDMDS production system.

In the DMDS production system, dimethyl disulfide can be produced fromthe methyl mercaptan and, for example, hydrogen peroxide and sodiumhydroxide. Often, at least about 80%, at least about 90%, at least about95%, or at least about 99%, of the methyl mercaptan can be converted inthe DMDS production system, and the yield of the dimethyl disulfide canbe at least about 80%, at least about 90%, at least about 95%, or atleast about 99% (these are molar yields based on the moles of methylmercaptan).

The ETE production system can consume at least a portion of the ethylmercaptan from the mercaptan production system. While not being limitedthereto, at least about 80 wt. % of the ethyl mercaptan from themercaptan production system generally is consumed in the ETE productionsystem. In some aspects, at least about 90 wt. %, at least about 95 wt.%, at least about 99 wt. %, or all or substantially all, of the ethylmercaptan from the mercaptan production system can be consumed in theETE production system.

In the ETE production system, ethylthioethanol can be produced from theethyl mercaptan and, for example, ethylene oxide. Often, at least about80%, at least about 90%, at least about 95%, or at least about 99% ofthe ethyl mercaptan can be converted in the ETE production system, andthe yield of the ethylthioethanol can be at least about 80%, at leastabout 90%, at least about 95%, or at least about 99% (these are molaryields based on the moles of ethyl mercaptan).

The MES production system can consume at least a portion of the dimethylsulfide and the diethyl sulfide (i.e., at least a portion of thedimethyl sulfide, or at least a portion of the diethyl sulfide, or atleast a portion of both the dimethyl sulfide and the diethyl sulfide)from the mercaptan production system. For example, at least about 75 wt.% of the diethyl sulfide from the mercaptan production system can beconsumed in the MES production system. In some aspects, at least about85 wt. %, at least about 95 wt. %, at least about 99 wt. %, or all orsubstantially all of the diethyl sulfide from the mercaptan productionsystem can be consumed in the MES production system.

In the MES production system, methyl ethyl sulfide can be produced fromthe dimethyl sulfide and the diethyl sulfide. In one aspect, the MESproduction system can comprise a reactor capable of reacting (orconfigured to react) the dimethyl sulfide and the diethyl sulfide in thepresence of a catalyst to form a reaction mixture containing the methylethyl sulfide. In another aspect, the MES production system can comprisea fixed bed reactor capable of reacting (or configured to react) thedimethyl sulfide and the diethyl sulfide in the vapor phase with a fixedbed of a catalyst to form a reaction mixture containing the methyl ethylsulfide. In these and other aspects, the reactor can be constructed ofany suitable stainless steel, non-limiting examples of which can includegrade 304, 316, 321, 347, 410S, 600, or 800 stainless steels, amongothers.

The reactor in the MES production system can be capable of operating (orconfigured to operate) at a temperature in a range from about 200° C. toabout 500° C. and at a pressure in a range from about 50 to about 500psig (344 to 3447 kPag). In a further aspect, the reactor in the MESproduction system can be capable of operating (or configured to operate)at a temperature in a range from about 250° C. to about 450° C. and at apressure in a range from about 100 to about 450 psig (689 to 3102 kPag).The catalyst used in the MES manufacturing system, whether employed in afixed bed reactor or not, can be any suitable supported or unsupportedhydrotreating catalyst or any catalyst disclosed herein, such as a CoMocatalyst, a NiMo catalyst, or γ-alumina, and the like, as well ascombinations thereof.

The reactor in the MES manufacturing system can be capable of reacting(or configured to react) the diethyl sulfide and an excess of thedimethyl sulfide in the presence of a catalyst to form a reactionmixture containing the methyl ethyl sulfide at any suitable percentconversion of the diethyl sulfide (and/or yield of the methyl ethylsulfide). Often, at least about 70%, at least about 80%, at least about90%, or at least about 95%, of the diethyl sulfide can be converted inthe MES reactor, and the yield of the methyl ethyl sulfide can be atleast about 70%, at least about 80%, at least about 90%, or at leastabout 95% (these are molar yields based on the moles of diethylsulfide).

As disclosed herein, the process for producing methyl ethyl sulfide canbe a continuous flow process. In such circumstances, the MES reactor canbe capable of reacting (or configured to react) the diethyl sulfide andan excess of the dimethyl sulfide in the presence of a catalyst to forma reaction mixture containing the methyl ethyl sulfide at any suitablesingle pass percent conversion of the diethyl sulfide (or yield of themethyl ethyl sulfide). Often, at least about 60%, at least about 70%, atleast about 75%, or at least about 80%, of the diethyl sulfide can beconverted in a single pass, and the single pass yield of the methylethyl sulfide can be at least about 60%, at least about 70%, at leastabout 75%, or at least about 80% (these are molar yields based on themoles of diethyl sulfide).

In addition to the reactor, the MES production system can comprise adownstream separations system capable of isolating (or configured toisolate) the methyl ethyl sulfide from the reaction mixture to form aproduct stream containing the methyl ethyl sulfide. In some aspects ofthis invention, the downstream separations system can be further capableof isolating (or configured to isolate) unreacted dimethyl sulfide anddiethyl sulfide from the reaction mixture, and recycling the unreacteddimethyl sulfide and diethyl sulfide to the reactor. While not beinglimited thereto, the downstream separations system can comprise one ormore than one distillation column.

The MES production system and the downstream separations system can becapable of forming (or configured to form) the product stream at apurity of the methyl ethyl sulfide in the product stream of at leastabout 90 wt. %, at least about 95 wt. %, at least about 97 wt. %, or atleast about 99 wt. %. These weight percentages are based on the amountof methyl ethyl sulfide in the product stream to the total weight of theproduct stream.

Further, the MES production system and the downstream separations systemcan be capable of forming (or configured to form) the product stream ata yield of the methyl ethyl sulfide in the product stream of at leastabout 70%, at least about 80%, at least about 90%, or at least about95%. These are molar yields based on the moles of diethyl sulfide.

An integrated mercaptan and sulfide manufacturing system, as describedherein, can contain a (i) a mercaptan production system, (ii) a DMDSproduction system, (iii) an ETE production system, and (iv) a MESproduction system. FIG. 1 illustrates a representative mercaptan andsulfide manufacturing system 100 consistent with the present invention.Mercaptan and sulfide manufacturing system 100 can include mercaptanproduction system 110, ETE (ethylthioethanol) production system 130,DMDS (dimethyl disulfide) production system 140, and MES (methyl ethylsulfide) production system 150. In FIG. 1, mercaptan production system110 includes alcohol reactant stream 102, which can feed methanol orethanol (or both) to mercaptan production system 110, and H₂S reactantstream 104, which can feed H₂S to mercaptan production system 110. Fromthese reactants, mercaptan production system 110 can produce methylmercaptan product stream 114 and dimethyl sulfide product stream 116(from the methanol and H₂S), as well as ethyl mercaptan product stream112 and diethyl sulfide product stream 118 (from the ethanol and H₂S).

Ethyl mercaptan product stream 112 can be split such that a portionbecomes ethyl mercaptan reactant stream 134, which can feed to ETEproduction system 130, as shown in FIG. 1. The remaining portion ofethyl mercaptan product stream 132 can be used for other purposes, suchas for sale/distribution or for use in other industrial/chemicalprocesses. ETE production system 130 also includes ethylene oxidereactant stream 136, and ETE production system 130 can produceethylthioethanol product stream 138 from the ethyl mercaptan andethylene oxide.

Although not shown, methyl mercaptan product stream 114 can be split ina similar manner to ethyl mercaptan product stream 112. In FIG. 1,methyl mercaptan feed stream 114 can feed directly to DMDS productionsystem 140. DMDS production system 140 also includes a feed stream forother reactants 144 (e.g., hydrogen peroxide and sodium hydroxide), andDMDS production system 140 can produce dimethyl disulfide product stream146 from the methyl mercaptan, hydrogen peroxide, and sodium hydroxide.

Storage tank system 120 can be used to store dimethyl sulfide fromdimethyl sulfide product stream 116 and diethyl sulfide from diethylsulfide product stream 118 for future use. Although not shown, storagetank system 120 also can store methyl mercaptan from methyl mercaptanproduct stream 114 and/or ethyl mercaptan from ethyl mercaptan productstream 112 for future use, if desired.

Dimethyl sulfide feed stream 122 exiting tank system 120 can be splitsuch that a portion becomes dimethyl sulfide reactant stream 154, whichcan feed to MES production system 150, as shown in FIG. 1. The remainingportion of dimethyl sulfide feed stream 152 can be used for otherpurposes, such as for sale/distribution or for use in otherindustrial/chemical processes. Although not shown, diethyl sulfidereactant stream 124 can be split in a similar manner to dimethyl sulfidefeed stream 122. In FIG. 1, diethyl sulfide reactant stream 124 can feeddirectly from tank system 120 to MES production system 150. MESproduction system 150 can produce methyl ethyl sulfide product stream156 from the dimethyl sulfide and the diethyl sulfide.

Integrated Mercaptan and Sulfide Production Processes

Aspects of this invention also are directed to integrated methods forproducing mercaptans and sulfides. Such processes can comprise, consistessentially of, or consist of (a) reacting methanol and H₂S to formmethyl mercaptan and dimethyl sulfide, (b) reacting ethanol and H₂S toform ethyl mercaptan and diethyl sulfide, (c) reacting at least aportion of the methyl mercaptan with hydrogen peroxide and sodiumhydroxide to form dimethyl disulfide, (d) reacting at least a portion ofthe ethyl mercaptan with ethylene oxide to form ethylthioethanol, and(e) reacting at least a portion of the dimethyl sulfide and the diethylsulfide to form methyl ethyl sulfide. Generally, the features of thisintegrated method are independently described herein and these featurescan be combined in any combination to further describe the disclosedintegrated method. Moreover, other process steps can be conductedbefore, during, and/or after any of steps (a)-(e), unless statedotherwise.

Generally, steps (a)-(e) can be conducted at any suitable reactionconditions (e.g., temperature, pressure, reactant ratio, etc.), as wouldbe recognized by those skilled in the art.

In step (a), methanol and H₂S can be reacted to form methyl mercaptanand dimethyl sulfide, and at least a portion of the methyl mercaptan canbe reacted with hydrogen peroxide and sodium hydroxide in step (c) toform dimethyl disulfide. While not limited thereto, at least about 75wt. %, at least about 85 wt. %, at least about 95 wt. %, or at leastabout 99 wt. %, of the methyl mercaptan produced in step (a) can beconsumed in step (c). Additionally, the conversion of methyl mercaptan(or molar yield to the dimethyl disulfide) in step (c) can be at leastabout 80%, at least about 90%, at least about 95%, or at least about99%.

In step (b), ethanol and H₂S can be reacted to form ethyl mercaptan anddiethyl sulfide, and at least a portion of the ethyl mercaptan can bereacted with ethylene oxide in step (d) to form ethylthioethanol. Anysuitable amount of the ethyl mercaptan produced in step (b) can beconsumed in step (d), ranging from less than 10 wt. % to over 90 wt. %.Additionally, the conversion of ethyl mercaptan (or molar yield to theethylthioethanol) in step (d) can be at least about 80%, at least about90%, at least about 95%, or at least about 99%.

Methanol and H₂S can be reacted to form methyl mercaptan and dimethylsulfide in step (a), and ethanol and H₂S can be reacted to form ethylmercaptan and diethyl sulfide in step (b). In step (e), at least aportion of the dimethyl sulfide and the diethyl sulfide can be reactedto form methyl ethyl sulfide. While not limited thereto, at least about75 wt. %, at least about 85 wt. %, at least about 95 wt. %, or at leastabout 99 wt. %, of the diethyl sulfide produced in step (b) can beconsumed in step (e). Any suitable amount of the dimethyl sulfideproduced in step (a) can be consumed in step (e), ranging from less than10 wt. % to over 90 wt. %.

Further, any features of the process for producing methyl ethyl sulfide(by contacting dimethyl sulfide, diethyl sulfide, and a catalyst to forma reaction mixture comprising the methyl ethyl sulfide) disclosed hereincan be applied to step (e). For instance, dimethyl sulfide and diethylsulfide can be reacted in the presence of a supported or unsupportedcatalyst (e.g., γ-alumina, a CoMo catalyst, or a NiMo catalyst), and thepercent conversion of the diethyl sulfide (or the molar yield to themethyl ethyl sulfide) in step (e) can be at least about 70%, at leastabout 80%, at least about 90%, or at least about 95%. Moreover, themethyl ethyl sulfide can be isolated from the reaction mixture using anysuitable technique (e.g., extraction, filtration, evaporation,distillation, or any combination thereof), to form a product streamcontaining the methyl ethyl sulfide. This product stream can contain,for instance, at least about 90 wt. %, at least about 95 wt. %, at leastabout 97 wt. %, or at least about 99 wt. %, of the methyl ethyl sulfide,based on the total weight of the product stream. Additionally oralternatively, unreacted dimethyl sulfide and unreacted diethyl sulfidecan be isolated from the reaction mixture, and recycled or re-used asreactants in step (e).

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, modifications, and equivalentsthereof, which after reading the description herein, can suggestthemselves to one of ordinary skill in the art without departing fromthe spirit of the present invention or the scope of the appended claims.

Gas Chromatograph (GC) analyses were conducted on an Agilent 7890A GCSystem, using an HP-5 column (dimethylpolysiloxane, capillary 30 m×0.32μm×0.25 μm nominal), with 35° C. temperature hold for 5 minutes followedby ramping at a rate of 5° C./min from 35° C. to 70° C., followed byramping at 15° C./min to 260° C., then holding at 260° C. for 10minutes. Standards for dimethyl sulfide (DMS), diethyl sulfide (DES),and methyl ethyl sulfide (MES) were used to identify the respectivereactants and products. Product composition information is presented inarea percentages (area %), unless otherwise specified.

Examples 1-16 Synthesis of methyl ethyl sulfide

For Example 1, dimethyl sulfide (DMS) and diethyl sulfide (DES) wereblended in a feed tank at an approximate weight ratio of 4:1 (DMS:DES),which was confirmed via GC. FIG. 2 is a GC plot of the blended feedcontaining DMS and DES. The respective amounts of DMS (eluting at 11min; 79.3%) and DES (eluting at 18 min; 20.7%) via area percentages arelisted in Table I.

The DMS and DES blend was fed into the top of a fixed bed reactorcontaining a mixed bed of (i) supported CoMo on alumina and (ii)γ-alumina at a total flow rate (DMS and DES) of 17 g/hr. The WHSV was0.1 (weight of DES which comes in contact with the catalyst per unittime, in g/g/hr). The fixed bed reactor had three independent heatingzones: the top zone of the reactor (5.71 g of γ-alumina and 6.85 g ofsupported CoMo), the middle zone of the reactor (8.41 g of γ-alumina and3.31 g of supported CoMo), and the bottom zone of the reactor (10.7 g ofγ-alumina). As shown in Table I, the reaction temperature wasapproximately 270-300° C., and the reaction pressure was 300 psig (2068kPag). Unexpectedly, 90% of the DES was converted, primarily to methylethyl sulfide (MES).

The same general procedure was used for Examples 2-4, and the resultsare summarized in Table I, with the respective amounts of DMS, DES, andMES in area percentages. The percent conversions of DMS, primarily toMES, were in the 70-80% range. FIG. 3 is a GC plot of the reactionmixture of Example 3, with DMS eluting at 11 min (˜67 area %), DESeluting at 18 min (˜4.5 area %), and MES eluting at 15 min (˜25 area %).

For Examples 5-9, the same general procedure for Example 1 was followed,except that the top zone of the reactor contained 6.92 of inert aluminaand 6.90 g of supported CoMo, the middle zone of the reactor contained3.82 g of inert alumina and 9.47 g of supported CoMo, and the bottomzone of the reactor contained 13.22 g of supported CoMo. The results aresummarized in Table I. Generally, the lower reaction temperatures usedin Examples 5-9 resulted in significantly lower conversions of DES.

For Examples 10-13, the same general procedure for Examples 5-9 wasfollowed. The results are summarized in Table I. The reactiontemperatures for Examples 11-13 were in the 270-380° C. range and,unexpectedly, 88-91% of the DES was converted, primarily to methyl ethylsulfide (MES). FIG. 4 is a GC plot of a reaction mixture representativeof Examples 5-13, with DMS eluting at 11 min, DES eluting at 18 min, andMES eluting at 15 min.

For Example 14, dimethyl sulfide (DMS) and diethyl sulfide (DES) wereblended in a feed tank at an approximate weight ratio of 4:1 (DMS:DES),along with approximately 4.7 wt. % of TBPS 454 di-tert-butyl polysulfide(CAS No. 68937-96-2), based on the total weight of the blended feed.While not wishing to be bound by the following theory, it is believedthat the TBPS 454 may decompose to free mercaptan and help initiate thereaction to produce MES. The blended feed was fed into the top of thefixed bed reactor containing only γ-alumina (33.5 g) at a WHSV of 0.2(weight of DES which comes in contact with the catalyst per unit time,in g/g/hr). The results are summarized in Table I. Unexpectedly, inExample 14, 80% of the DES was converted using only γ-alumina (no CoMoor NiMo), primarily to methyl ethyl sulfide (MES).

For Example 15, the same general procedure for Example 14 was followed,except that the flow rate was reduced to result in a WHSV of 0.1 (seeTable I). Unexpectedly, 87% of the DES was converted using onlyγ-alumina (no CoMo or NiMo), primarily to methyl ethyl sulfide (MES).FIG. 5 is a GC plot of a reaction mixture representative of Examples14-15, with DMS eluting at 11 min, DES eluting at 18 min, and MESeluting at 15 min.

Beneficially, and unexpectedly, few by-products were observed inExamples 1-15, and thus purification of the crude MES product would notbe problematic. Also surprisingly, only a small amount of methylmercaptan (MeSH) was present in the reactor effluent; MeSHconcentrations were approximately ˜0.5-3 wt. % in the reactor effluent,regardless of the catalyst used. Ethyl mercaptan was present at muchless than 1 wt. % in the reactor effluent, and often not detectable.

For Example 16, the conditions of Example 14 were utilized, except thatthe feed ratio of dimethyl sulfide (DMS) and diethyl sulfide (DES) wasreversed, such that DMS was the limiting reactant. The molar ratio ofDES:DMS was 5:1 in Example 16. Similar to Examples 1-15, MES wasproduced in Example 16.

TABLE I Summary of Examples 1-15. DES Top Middle Bottom FlowratePressure DMS MES DES Conversion Example WHSV (° C.) (° C.) (° C.) (g/hr)(psig) (%) (%) (%) (%) Feed — — — — — — 79.30 0.00 20.70 — 1 0.10 269301 296 17 301 49.13 17.82 1.97 90.5 2 0.10 294 309 304 17 295 67.8726.50 3.93 81.0 3 0.10 294 301 298 17 300 67.41 25.36 4.51 78.2 4 0.05292 302 298 9 298 68.16 23.40 5.88 71.6 5 0.10 261 149 107 15 313 68.654.87 11.66 43.7 6 0.10 272 143 99 15 310 68.68 16.90 8.69 58.0 7 0.42200 139 29 60 308 67.04 20.18 12.78 38.2 8 0.42 291 188 148 60 294 73.529.67 15.44 25.4 9 0.42 292 190 154 60 294 73.45 9.82 15.37 25.7 10 0.10333 179 122 15 303 72.92 15.13 10.02 51.6 11 0.10 340 381 340 15 30360.83 17.95 2.46 88.1 12 0.10 281 286 269 15 298 64.24 25.84 2.12 89.713 0.10 299 306 297 15 300 65.66 25.54 2.01 90.3 14 0.20 297 282 199 33318 60.99 30.61 4.08 80.3 15 0.10 299 281 185 17 308 62.49 28.57 2.7486.8

The invention is described above with reference to numerous aspects andspecific examples. Many variations will suggest themselves to thoseskilled in the art in light of the above detailed description. All suchobvious variations are within the full intended scope of the appendedclaims. Other aspects of the invention can include, but are not limitedto, the following (aspects are described as “comprising” but,alternatively, can “consist essentially of” or “consist of”):

Aspect 1. A process for producing methyl ethyl sulfide, the processcomprising contacting (a) dimethyl sulfide, (b) diethyl sulfide, and (c)a catalyst, to form a reaction mixture comprising the methyl ethylsulfide.

Aspect 2. The process defined in aspect 1, wherein the dimethyl sulfideand the diethyl sulfide are combined prior to contacting the catalyst.

Aspect 3. The process defined in aspect 1 or 2, wherein the step ofcontacting is conducted at a temperature in any suitable range or anyrange disclosed herein, e.g., from about 200° C. to about 500° C., fromabout 125° C. to about 400° C., or from about 250° C. to about 350° C.

Aspect 4. The process defined in any one of the preceding aspects,wherein the step of contacting is conducted at a pressure in anysuitable range or any range disclosed herein, e.g., from about 50 toabout 850 psig (344 to 5860 kPag), from about 50 to about 500 psig (344to 3447 kPag), or from about 150 to about 400 psig (1034 to 2758 kPag).

Aspect 5. The process defined in any one of the preceding aspects,wherein a molar ratio of dimethyl sulfide to diethyl sulfide (DMS:DES)is in any suitable range or any range disclosed herein, e.g., from about10:1 to about 1:10, from about 5:1 to about 1:5, or from about 2:1 toabout 1:2.

Aspect 6. The process defined in any one of the preceding aspects,wherein the diethyl sulfide is a limiting reactant in the production ofthe methyl ethyl sulfide.

Aspect 7. The process defined in any one of the preceding aspects,wherein a molar ratio of dimethyl sulfide to diethyl sulfide (DMS:DES)is in any suitable range or any range disclosed herein, e.g., from about1.5:1 to about 10:1, from about 4:1 to about 20:1, or from about 2:1 toabout 6:1.

Aspect 8. The process defined in any one of the preceding aspects,wherein the process comprises contacting (a) the dimethyl sulfide and(b) the diethyl sulfide in the vapor phase with (c) the catalyst (e.g.,the solid catalyst).

Aspect 9. The process defined in any one of the preceding aspects,wherein the process comprises contacting (a) the dimethyl sulfide and(b) the diethyl sulfide with a fixed bed of (c) the catalyst.

Aspect 10. The process defined in any one of the preceding aspects,wherein the process further comprises contacting (a) the dimethylsulfide, (b) the diethyl sulfide, (c) the catalyst, and (d) any suitablesulfur-containing compound (e.g., H₂S, CS₂, di-tert-butyl polysulfide,etc., or any combination thereof) at any suitable amount or an amount inany range disclosed herein, e.g., less than or equal to about 5 mol %,less than or equal to about 3 mol %, or less than about 1 mol %, basedon the moles of the limiting reactant.

Aspect 11. The process defined in any one of the preceding aspects,wherein the step of contacting is conducted at any suitable WHSV or aWHSV in any range disclosed herein, e.g., from about 0.01 to about 3, orfrom about 0.05 to about 1.

Aspect 12. The process defined in any one of the preceding aspects,wherein the catalyst comprises any suitable catalyst or any catalystdisclosed herein, e.g., a solid hydrotreating catalyst such as a CoMocatalyst or a NiMo catalyst, γ-alumina, a zeolite, or any combinationthereof.

Aspect 13. The process defined in aspect 13, wherein the catalystcomprises the catalyst supported on any suitable solid oxide or anysolid oxide disclosed herein, e.g., silica, alumina, silica-alumina,aluminum phosphate, zinc aluminate, zirconia, thoria, etc., or anycombination thereof.

Aspect 14. The process defined in any one of the preceding aspects,wherein a conversion of the limiting reactant (or the yield to themethyl ethyl sulfide) is any percent conversion (or yield) disclosedherein, e.g., at least about 50%, at least about 70%, at least about80%, at least about 90%, or at least about 95%.

Aspect 15. The process defined in any one of the preceding aspects,wherein a single pass conversion of the limiting reactant (or the singlepass yield to the methyl ethyl sulfide) is any single pass percentconversion (or single pass yield) disclosed herein, e.g., at least about40%, at least about 60%, at least about 70%, at least about 75%, or atleast about 80%.

Aspect 16. The process defined in any one of the preceding aspects,further comprising a step of isolating the methyl ethyl sulfide from thereaction mixture using any suitable technique or any technique disclosedherein, e.g., extraction, filtration, evaporation, distillation, or anycombination thereof, to form a product stream containing the methylethyl sulfide.

Aspect 17. The process defined in aspect 16, wherein isolating comprisesa distillation step.

Aspect 18. The process defined in aspect 16 or 17, wherein a yield ofthe methyl ethyl sulfide in the product stream is at least about 50%, atleast about 70%, at least about 80%, at least about 90%, or at leastabout 95%, based on the limiting reactant.

Aspect 19. The process defined in any one of aspects 16-18, wherein apurity of the methyl ethyl sulfide in the product stream is at leastabout 80 wt. %, at least about 90 wt. %, at least about 95 wt. %, atleast about 97 wt. %, or at least about 99 wt. %, based on the totalweight of the product stream.

Aspect 20. An integrated mercaptan and sulfide manufacturing systemcomprising:

(i) a mercaptan production system capable of producing methyl mercaptanand dimethyl sulfide from methanol and H₂S and capable of producingethyl mercaptan and diethyl sulfide from ethanol and H₂S;

(ii) a DMDS production system for consuming at least a portion of themethyl mercaptan from the mercaptan production system, wherein the DMDSproduction system is capable of producing dimethyl disulfide from themethyl mercaptan (and, for example, hydrogen peroxide and sodiumhydroxide);

(iii) an ETE production system for consuming at least a portion of theethyl mercaptan from the mercaptan production system, wherein the ETEproduction system is capable of producing ethylthioethanol from theethyl mercaptan (and, for example, ethylene oxide); and

(iv) a MES production system for consuming at least a portion of thedimethyl sulfide and the diethyl sulfide from the mercaptan productionsystem, wherein the MES production system is capable of producing methylethyl sulfide from the dimethyl sulfide and the diethyl sulfide.

Aspect 21. The manufacturing system defined in aspect 20, wherein theMES production system comprises a reactor capable of reacting thedimethyl sulfide and the diethyl sulfide in the presence of a catalystto form a reaction mixture containing the methyl ethyl sulfide.

Aspect 22. The manufacturing system defined in aspect 20, wherein theMES production system comprises a fixed bed reactor capable of reactingthe dimethyl sulfide and the diethyl sulfide in the vapor phase with afixed bed of a catalyst to form a reaction mixture containing the methylethyl sulfide.

Aspect 23. The manufacturing system defined in aspect 21 or 22, whereinthe reactor is capable of operating at a temperature in a range fromabout 200° C. to about 500° C. and at a pressure in a range from about50 to about 500 psig (344 to 3447 kPag).

Aspect 24. The manufacturing system defined in any one of aspects 21-23,wherein the reactor is constructed of any suitable stainless steel orany stainless steel disclosed herein, e.g., grade 304, 316, 321, 347,410S, 600, or 800 stainless steel.

Aspect 25. The manufacturing system defined in any one of aspects 21-24,wherein the catalyst comprises a supported or unsupported hydrotreatingcatalyst, e.g., a CoMo catalyst or a NiMo catalyst.

Aspect 26. The manufacturing system defined in any one of aspects 21-25,wherein the reactor is capable of reacting the diethyl sulfide and anexcess of the dimethyl sulfide in the presence of a catalyst to form areaction mixture containing the methyl ethyl sulfide at any percentconversion of the diethyl sulfide (or yield to the methyl ethyl sulfide)disclosed herein, e.g., at least about 70%, at least about 80%, at leastabout 90%, or at least about 95%.

Aspect 27. The manufacturing system defined in any one of aspects 21-26,wherein the reactor is capable of reacting the diethyl sulfide and anexcess of the dimethyl sulfide in the presence of a catalyst to form areaction mixture containing the methyl ethyl sulfide at any single passpercent conversion of the diethyl sulfide (or single pass yield to themethyl ethyl sulfide) disclosed herein, e.g., at least about 60%, atleast about 70%, at least about 75%, or at least about 80%.

Aspect 28. The manufacturing system defined in any one of aspects 21-27,wherein the MES production system comprises a downstream separationssystem capable of isolating the methyl ethyl sulfide from the reactionmixture to form a product stream containing the methyl ethyl sulfide.

Aspect 29. The manufacturing system defined in aspect 28, wherein thedownstream separations system is further capable of isolating unreacteddimethyl sulfide and diethyl sulfide from the reaction mixture, andrecycling the unreacted dimethyl sulfide and diethyl sulfide to thereactor.

Aspect 30. The manufacturing system defined in aspect 28 or 29, whereinthe downstream separations system is capable of forming the productstream at a purity of the methyl ethyl sulfide in the product stream ofat least about 90 wt. %, at least about 95 wt. %, at least about 97 wt.%, or at least about 99 wt. %, based on the total weight of the productstream.

Aspect 31. The manufacturing system defined in any one of aspects 28-30,wherein the downstream separations system is capable of forming theproduct stream at a yield of the methyl ethyl sulfide in the productstream of at least about 70%, at least about 80%, at least about 90%, orat least about 95%, based on the diethyl sulfide.

Aspect 32. The manufacturing system defined in any one of aspects 28-31,wherein the downstream separations system comprises at least onedistillation column.

Aspect 33. The manufacturing system defined in any one of aspects 20-32,wherein at least about 75 wt. %, at least about 85 wt. %, at least about95 wt. %, or at least about 99 wt. %, of the methyl mercaptan from themercaptan production system is consumed in the DMDS production system.

Aspect 34. The manufacturing system defined in any one of aspects 20-33,wherein at least about 75 wt. %, at least about 85 wt. %, at least about95 wt. %, or at least about 99 wt. %, of the diethyl sulfide from themercaptan production system is consumed in the MES production system.

Aspect 35. The manufacturing system defined in any one of aspects 20-34,wherein the DMDS production system is capable of converting at leastabout 80%, at least about 90%, at least about 95%, or at least about99%, of the methyl mercaptan to the dimethyl disulfide.

Aspect 36. The manufacturing system defined in any one of aspects 20-35,wherein the ETE production system is capable of converting at leastabout 80%, at least about 90%, at least about 95%, or at least about99%, of the ethyl mercaptan to the ethylthioethanol.

Aspect 37. An integrated method for producing mercaptans and sulfides,the method comprising: (a) reacting methanol and H₂S to form methylmercaptan and dimethyl sulfide, (b) reacting ethanol and H₂S to formethyl mercaptan and diethyl sulfide, (c) reacting at least a portion ofthe methyl mercaptan with hydrogen peroxide and sodium hydroxide to formdimethyl disulfide, (d) reacting at least a portion of the ethylmercaptan with ethylene oxide to form ethylthioethanol, and (e) reactingat least a portion of the dimethyl sulfide and the diethyl sulfide toform methyl ethyl sulfide.

Aspect 38. The method defined in aspect 37, wherein the dimethyl sulfideand the diethyl sulfide are reacted in the presence of a catalyst toform a reaction mixture containing the methyl ethyl sulfide.

Aspect 39. The method defined in aspect 38, wherein the catalystcomprises a supported or unsupported hydrotreating catalyst, e.g., aCoMo catalyst or a NiMo catalyst.

Aspect 40. The method defined in any one of aspects 37-39, wherein apercent conversion of the diethyl sulfide (or yield to the methyl ethylsulfide) is any percent conversion (or yield) disclosed herein, e.g., atleast about 70%, at least about 80%, at least about 90%, or at leastabout 95%.

Aspect 41. The method defined in any one of aspects 38-40, furthercomprising a step of isolating the methyl ethyl sulfide from thereaction mixture using any suitable technique or any technique disclosedherein, e.g., extraction, filtration, evaporation, distillation, or anycombination thereof, to form a product stream containing the methylethyl sulfide.

Aspect 42. The method defined in aspect 41, wherein a purity of themethyl ethyl sulfide in the product stream is at least about 90 wt. %,at least about 95 wt. %, at least about 97 wt. %, or at least about 99wt. %, based on the total weight of the product stream.

Aspect 43. The method defined in any one of aspects 38-42, furthercomprising a step of isolating unreacted dimethyl sulfide and diethylsulfide from the reaction mixture, and recycling the unreacted dimethylsulfide and diethyl sulfide.

Aspect 44. The method defined in any one of aspects 37-43, wherein atleast about 75 wt. %, at least about 85 wt. %, at least about 95 wt. %,or at least about 99 wt. %, of the methyl mercaptan produced in step (a)is consumed in step (c).

Aspect 45. The method defined in any one of aspects 37-44, wherein atleast about 75 wt. %, at least about 85 wt. %, at least about 95 wt. %,or at least about 99 wt. %, of the diethyl sulfide produced in step (b)is consumed in step (e).

Aspect 46. The method defined in any one of aspects 37-45, wherein atleast about 80%, at least about 90%, at least about 95%, or at leastabout 99%, of the methyl mercaptan is converted to the dimethyldisulfide in step (c).

Aspect 47. The method defined in any one of aspects 37-46, wherein atleast about 80%, at least about 90%, at least about 95%, or at leastabout 99%, of the ethyl mercaptan is converted to the ethylthioethanolin step (d).

We claim:
 1. An integrated mercaptan and sulfide manufacturing systemcomprising: (i) a mercaptan production system capable of producingmethyl mercaptan and dimethyl sulfide from methanol and H₂S, and capableof producing ethyl mercaptan and diethyl sulfide from ethanol and H₂S;(ii) a DMDS production system for consuming at least a portion of themethyl mercaptan from the mercaptan production system, wherein the DMDSproduction system is capable of producing dimethyl disulfide from themethyl mercaptan; (iii) an ETE production system for consuming at leasta portion of the ethyl mercaptan from the mercaptan production system,wherein the ETE production system is capable of producingethylthioethanol from the ethyl mercaptan; and (iv) a MES productionsystem for consuming at least a portion of the dimethyl sulfide and thediethyl sulfide from the mercaptan production system, wherein the MESproduction system is capable of producing methyl ethyl sulfide from thedimethyl sulfide and the diethyl sulfide.
 2. The manufacturing system ofclaim 1, wherein the MES production system comprises a reactor capableof reacting the dimethyl sulfide and the diethyl sulfide in the presenceof a catalyst to form a reaction mixture containing the methyl ethylsulfide.
 3. The manufacturing system of claim 1, wherein the MESproduction system comprises a fixed bed reactor capable of reacting thedimethyl sulfide and the diethyl sulfide in the vapor phase with a fixedbed of a catalyst to form a reaction mixture containing the methyl ethylsulfide.
 4. The manufacturing system of claim 3, wherein the MESproduction system comprises a downstream separations system capable ofisolating the methyl ethyl sulfide from the reaction mixture to form aproduct stream containing the methyl ethyl sulfide.
 5. The manufacturingsystem of claim 4, wherein the downstream separations system is furthercapable of isolating unreacted dimethyl sulfide and diethyl sulfide fromthe reaction mixture, and recycling the unreacted dimethyl sulfide anddiethyl sulfide to the reactor.
 6. The manufacturing system of claim 1,wherein: at least about 85 wt. % of the methyl mercaptan from themercaptan production system is consumed in the DMDS production system;and at least about 85 wt. % of the diethyl sulfide from the mercaptanproduction system is consumed in the MES production system.
 7. Anintegrated method for producing mercaptans and sulfides, the methodcomprising: (a) reacting methanol and H₂S to form methyl mercaptan anddimethyl sulfide; (b) reacting ethanol and H₂S to form ethyl mercaptanand diethyl sulfide; (c) reacting at least a portion of the methylmercaptan with hydrogen peroxide and sodium hydroxide to form dimethyldisulfide; (d) reacting at least a portion of the ethyl mercaptan withethylene oxide to form ethylthioethanol; and (e) reacting at least aportion of the dimethyl sulfide and the diethyl sulfide to form methylethyl sulfide.
 8. The method of claim 1, wherein at least about 75 wt. %of the methyl mercaptan produced in step (a) is consumed in step (c). 9.The method of claim 7, wherein at least about 75 wt. % of the diethylsulfide produced in step (b) is consumed in step (e).
 10. Themanufacturing system of claim 1, wherein the DMDS production system iscapable of converting at least about 90 mol % of the methyl mercaptan tothe dimethyl disulfide.
 11. The manufacturing system of claim 1, whereinthe ETE production system is capable of converting at least about 90 mol% of the ethyl mercaptan to the ethylthioethanol.
 12. The manufacturingsystem of claim 2, wherein the catalyst comprises a supported CoMocatalyst, a supported NiMo catalyst, γ-alumina, a zeolite, or anycombination thereof.
 13. The manufacturing system of claim 2, whereinthe reactor is constructed of a stainless steel.
 14. The manufacturingsystem of claim 4, wherein the downstream separations system comprisesat least one distillation column.
 15. The manufacturing system of claim4, wherein the downstream separations system is capable of forming theproduct stream at a purity of the methyl ethyl sulfide in the productstream of at least about 90 wt. %, based on the total weight of theproduct stream.
 16. The manufacturing system of claim 4, wherein thedownstream separations system is capable of forming the product streamat a yield of the methyl ethyl sulfide in the product stream of at leastabout 80 mol %, based on the diethyl sulfide.
 17. The method of claim 7,wherein: the dimethyl sulfide and the diethyl sulfide are reacted in thepresence of a catalyst to form a reaction mixture containing the methylethyl sulfide; and the catalyst comprises a supported CoMo catalyst, asupported NiMo catalyst, γ-alumina, a zeolite, or any combinationthereof.
 18. The method of claim 17, further comprising a step ofisolating unreacted dimethyl sulfide and diethyl sulfide from thereaction mixture, and recycling the unreacted dimethyl sulfide anddiethyl sulfide.
 19. The method of claim 17, further comprising a stepof isolating the methyl ethyl sulfide from the reaction mixture to forma product stream containing the methyl ethyl sulfide.
 20. The method ofclaim 19, wherein a purity of the methyl ethyl sulfide in the productstream is at least about 90 wt. %, based on the total weight of theproduct stream.
 21. The method of claim 7, wherein: at least about 90mol % of the methyl mercaptan is converted to the dimethyl disulfide instep (c); and/or at least about 90 mol % of the ethyl mercaptan isconverted to the ethylthioethanol in step (d).